A thief sees a jeep at a distance of 250 m, coming towards him at 36 km/h. Thief takes 5 seconds to realize that the police is approaching him by the jeep and started running away from police at 54 km/hr. But police realized after 10 seconds, when the thief starts running away, that he is actually a thief and started chasing at 72 km/hr. What is the total distance and total time covered if thief is caught?
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We convert the speeds to m/s
36 × 5/18 = 10m/s
54 × 5/18 = 15 m/s
72 × 5/18 = 20 m/s
In 5 seconds the police covers :
10 × 10 = 50m
Remaining distance = 250 - 50 = 200m
In 10 seconds the thief covers :
15 × 10 = 150m
The police covers 10 × 10 = 100m
The remaining distance out of the 200m is 100 m
The distance between the police and the thief is :
150 + 100 = 250 m
This is the relative distance between the thief and the police at the time the police begin moving at 72km / h
The relative speed is :
20 - 15 = 5m/s
The time taken to catch up with the thief is :
250/5 = 50 seconds
The distance covered is 250 m
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